1. Technical Field
The present invention generally relates to a heat sink. More particularly, the present invention relates to a heat sink for free convection cooling in horizontal applications.
2. Background Art
As consumer electronic products become more advanced, the need to provide improved cooling of internal electronic components increases. Specifically, products such as laptop computers are being designed to have increased capabilities while being smaller in size. In previous larger products, forced convection cooling was often implemented. Forced convection cooling generally includes the use of a heat sink and a fan. For example, the heat sink could be positioned between the fan and a surface to be cooled (e.g., a microelectronic device). As the fan creates an air flow through the heat sink, heat is transferred from the surface. Unfortunately, such fans are often bulky and significantly add to the cost and size of the product. In addition, there are often a limited number of locations within a product where a fan can be placed.
Heretofore, many have attempted to solve these problems by using heat sinks with free convection cooling. In these applications the base of the heat sink is generally mounted in thermal contact with the surface to be cooled. Fins or pins attached to the base aid in the transfer of heat from the surface. However, the entire array of fins is generally supported by a solid base: when used in a horizontal application the base prevents air from flowing vertically through the fins. Thus, heat can only be removed from air that penetrates the sides of the heat sink.
In addition, existing heat sinks often utilize bases that are entirely flat. Although this could allow the base to be positioned flatly on the surface to be cooled, it unnecessarily restricts air flow around or under the base. Since air flow is the driving force behind convection cooling, and free convection cooling does not utilize a fan or the like, the cooling operation with such existing devices is less efficient.
In view of the forgoing, there exists a need for a heat sink for convection cooling in horizontal applications such as microelectronic devices. A need also exists for a heat sink that has a base and spaced apart cooling fins. A further need exists for the cooling fins to extend beyond an outer edge of the base so that air can flow horizontally beneath the base and then vertically through the spaced apart cooling fins. In addition, a further need exists for the base to be angled in order to increase the amount of air that can flow around and under the base for improved cooling. Furthermore, a need exists for such a heat sink to have a geometry that is compatible with extrusion in order to minimize its cost.